Various types of braking systems are known. For example, hydraulic, pneumatic and electromechanical braking systems have been developed for different applications.
An aircraft presents a unique set of operational and safety issues. For example, uncommanded braking due to failure can be dangerous to an aircraft during takeoff. On the other hand, it is similarly necessary to have virtually fail-proof braking available when needed (e.g., during landing). Moreover, it is important that braking be effected promptly and reliably.
A typical hydraulic brake system, for example, may include the following components among others: a pressure source, a brake actuator for exerting a braking force on a wheel as a result of pressure provided by the pressure source, a valve for controlling an amount of pressure provided from the pressure source to the actuator in response to a command signal, a controller for outputting the command signal in response to system inputs provided to the controller, and a wheel speed sensor. In many such systems, the system inputs include both operator input (e.g., depression of a brake pedal), and measured pressure or force applied to the actuator in response to the operator input.